Field of the Invention
The invention relates in general to integrated circuits, and more particularly to a single-end amplifier and a noise cancelling method thereof.
Description of the Related Art
In an integrated circuit, ripples and noises in an input power affect circuit performance. Thus, in circuits sensitive to ripples and noises, the cancellation of ripples and noises is first carried out, and a newly generated input power is then provided to a circuit to ensure the performance of the circuit.
In an actual circuit, especially in a single-end amplifying circuit, a power management integrated chip (PMIC) and a low dropout (LDO) linear regulator is frequently employed to reduce ripples and noises. However, due to the resonance between a welding capacitor and an on-chip capacitor, certain ripples and noise peaks inevitably exist in the bandwidth such that the performance of the circuit may be significantly degraded. In current technologies, a negative feedback loop or a filter capacitor is usually added to further suppress the ripples and noises. Such design may be needed for specific circuits, leading to not only circuit complications but also increased additional power consumption.